A:F1>F2>F3
B:F1=F2=F3
C:F1<F2<F3
D:F1>F3>F2
—I have difficulty in learning Chinese. Could you give me some help?
—Sure. Reading a lot will help you improve your Chinese.
规定图形 表示运算a﹣b+c,图形 表示运算x+z﹣y﹣w.则 + =____ (直接写出答案).